According to Healthline, ear infections occur when the Eustachian tubes that link the ear to the throat become swollen or blocked due to allergies, sinus infections and cold viruses. The blockages cause excess fluid and bacteria to build up behind the eardrum, which in turn can lead to infection.
WebMD explains that symptoms of an ear infection can include pain in the ear, thick drainage from the ear that is yellow or tinged with blood, fever and vomiting. If excess fluid has built up behind the eardrum, symptoms can include hearing difficulty, loss of balance, vertigo and ear pressure.
Mayo Clinic explains that external otitis, also referred to as swimmer's ear, is an infection of the outer ear canal caused by bacteria that invades the skin inside the canal. The infection often occurs in swimmers with excess water in their ears as the fluid creates a breeding ground for bacteria. Swimmer's ear can also be occur when the outer ear canal becomes irritated by scratching or insertion of cotton swabs. Symptoms of swimmer's ear include itchy ear canals, inflammation inside the ear, pain that is exacerbated when the earlobes are pulled, discharge and muffled hearing. If the infection continues to fester, symptoms can worsen and can include intense pain that travels to the face or head, swollen glands, fever and heavy fluid drainage.